Method and apparatus for producing dish-shaped articles

ABSTRACT

A method and apparatus are disclosed for forming dish-shaped articles from a circular blank by spinning operations. Spinning rollers having large radius shoulders are guided by template control means along a first path to spin the blank to form a curved intermediate shape at a first high speed operation. The intermediate shape is then subjected to a draw spin operation with a smaller radius shoulder guided by a second template control means along a second path distinct from the first path. The speed of operation for the second path is controlled to uniform deformation energy for the second run.

United States atent [191 Schriider et al.

[ July 16, 1974 METHOD AND APPARATUS FOR PRODUCING DISH-SHAPED ARTICLES[75] Inventors: Paul Schriider, Hamm; Giinter Pollkiitter, Ahlen, bothof Germany [30] Foreign Application Priority Data Nov. 15, 1971 Germany2156551 [52] US. Cl 72/85, 72/83, 29/159 R, 29/159.3 [51] Int. Cl ..B21d22/16, B2ld 22/18 [58] Field of Search 72/80-86; 29/159 A, 159.3, 159 R[5 6] References Cited UNITED STATES PATENTS 3,029,764 4/1962 Sporck72/85 3,141,433 7/1964 Bosch 72/81 3,195,491 7/1965 Bulgrin et a1. 72/823,282,078 11/1966 Kaesemeyer 72/82 FOREIGN PATENTS OR APPLICATIONS1,959,720 11/1969 Germany 72/84 Primary Examiner-Richard J. HerbstAttorney, Agent, or Firm-Fitch, Even, Tabin & Luedeka 5 7] ABSTRACT Amethod and apparatus are disclosed for forming dish-shaped articles froma circular blank by spinning operations. Spinning rollers having largeradius shoulders are guided by template control means along a first pathto spin the blank to form a curved intermediate shape at a first highspeed operation. The intermediate shape is then subjected to a draw spinoperation with a smaller radius shoulder guided by a second templatecontrol means along a second path distinct from the first path. Thespeed of operation for the second path is controlled to uniformdeformation energy for the second run.

7 Claims, 1 Drawing Figure METHOD AND APPARATUS FOR PRODUCINGDISH-SHAPED ARTICLES The present invention relates to a method ofproducing dish-shaped articles by a spinning or draw spinning operationwhereby a circular disc or ronde is drawn on a spinning chuck, and adraw spinning machine for performing such method.

The method and the apparatus according to the invention serve to producedish-shaped bodies or articles, especially wheel discs or dishes fore.g. trucks, by a non-cutting shaping operation.

It is known to produce wheel dishes by deep drawing in a press, wherebythe edge of the circular disc or ronde used must be rolled in advance toa tapering configuration in a disc rolling mill at forging temperature.

Accordingly, this method of production is uneconomically expensive, andthe wheel dishes produced thereby, moreover, are not true to shape orsize, respectively.

Furthermore, it is known first to spin wheel dishes on a spinning latheaccording'to the published German Patent application No. 1,285,436 inone pass of operation on a fixed spinning die, and then to draw thewheel dishes by means of a trailing roller. It is of disadvantage thatthis principle does not permit the use of materials of higher strengthbecause spin shaping of high strength materials is not possible in onesingle pass from a ronde or circular disc to a wheel dish shape due tothe inherent strength, since this would result in breakage of thematerial. Besides, this method results in that the final wheel dishexpands resiliently to greater degree, so that it is not sufficientlyexact to shape and size. The expansion or swelling of the finally shapedwheel dish is approximately proportional to the preceding spin shapingwork.

In contrast with this method, it is the object of the invention toprovide a method and a draw spinning machine for producing dish-shapedarticles and especially wheel discs or dishes, by means of which evenmaterials Advantageously, the shaping into the temporary shape orintermediate form can be performed by spin shaping in air, i.e. withoutabutment, and the temporary shape can be formed in one or more passes ofthe spin roller. In order to speed up the shaping process, the spinningof the temporary shape can be effected at substantially higher shapingrates than the production of the final shape, and the spinning and/ordraw spinning can be effected in any position of the roller pass, whilepermitting accommodation of the respective shaping requirements, with arate of shaping (speed of advance) adjusted as desired.

As a further advantageous feature, the finished workpiece may be clampedbetween the ejector and the headstock spindle and, while avoiding damageto the spinning chuck, may be pushed off the spinning chuck.

Advantageously, the draw spinning machine according to the invention andhaving two or more draw spinning rollers is characterized in that eachroller comprises a separate copying system consisting of a main templateand a copying cylinder, for the control thereof. Advantageously, in thedraw spinning machine which are difficult to shape may be shaped withtheir I wall thickness reduced to any desired degree, whereby it iscontemplated that the finished workpiece has maximum accuracy to size orshape, that a uniform structure is formed in the material used, that theshaping energy to be applied remains low, and that it is possible inparticular to perform the production in economical, safe, trouble-freeand rapid manner and fully automatically.

In the method outlined at the beginning, this object is solved accordingto the invention in that said ronde is first shaped into a dish-shapedintermediate form or temporary shape by a spinning operation, andthereafter brought into the final shape by a draw spinning operationwith continuous deformation energy.

By means of the small proportion of spinning and shaping work in thesecond pass of operation, it is obtained according to the invention thatthe spring-back resilience of the finished wheel dish is maintainedwithin very narrow limits, so that high accuracy to shape of the wheeldish is obtained. Likewise, the springback resilience is reduced to aminimum in dependency of the tolerances of the stock or startingmaterial which actually cannot be compensated by influencing the tooland the mode of control.

according to the invention each main template may have associatedtherewith a movable auxiliary template facilitating the production ofthe temporary shape by spinning in air, i.e. without abutment, wherebyeach auxiliary template may have associated therewith a moving elementdisplacing the contour of the auxiliary template behind the contour ofthe main template, while, furthermore, the main and auxiliary templatesof the individual roller units advantageously may be formed withdifferent configurations for adjusting any desired any different path oftravel of the rollers.

In another advantageous embodiment, the draw spinning machine accordingto the invention may include contact elements for the adjustment of thecontinuous shaping operation, which contact elements are adapted to beset during the working passes to any desired rates of advance which joineach other with continuous transition on the control desk.

In order to simplify the draw spinning machine according to theinvention, it may be operated with combined spinning and draw spinningrollers, whereby the front peripheral region of the combined drawspinning rollers may form a spinning roller having a large radius whilea smaller drawing radius may join the spinning shoulder of the roller,which smaller radius is active during the final shaping process. Theindividual draw spinning rollers may have different peripheral contoursand may operate in different positions.

In the following, an exemplary embodiment of the invention is explained.in greater detail by means of a drawing showing schematically theshaping portion of a draw spinning machine according to the invention.

The method according to the invention cannot readily be compared withthe known method according to the abovementioned published German Patentapplication No. 1,285,436, because the spinning and drawing orstretching operation on a wheel disc or dish of readily deformable steelmay be performed in one single run of operation and with one pair ofrollers only.

According to the invention, a second run of operation within the sameclamping period of the workpiece precedes the final draw spinningoperation. In such preceding run, a temporary shape is formed byspinning in air, i.e. without abutment, which temporary shape is thenbrought into the final shape by a draw spinning operation by employing acontinuous shaping work, so that even materials which are difficult toshape, may be shaped within one clamping period.

By the use of continuous shaping work during the final draw spinningoperation, a uniform structure or texture is obtained in the workpiece,whereas heretofore the most various types of structure were presentwithin the workpiece. The continuous shaping work for obtaining thefinal shape may comprise, on the one hand, a shaping work by spinning(urging the material against the chuck) or by draw or stretch spinning(reduction of the wall thickness by means of spinning rolers) or, on theother hand, the addition of the two shaping operations. In this case, ithas to be noted that a small amount of shaping work for the drawspinning results with a high amount of shaping work for the spinningoperation and vice versa.

The first pass for spinning the workpiece in the air, i.e. withoutabutment against the spinning chuck, can be effected in extremely rapidmanner. In this way, it is obtained in a manner being surprising to theexpert that the complete shaping operation does not take more time thanin conventional machines, although a dual pass (over the workpiece) ismade. In view of the fact that substantial shaping energy has beenapplied in the first spinning operation, the second draw spinningoperation may be performed faster than in the known methods, too.

Also, it is surprising to the expert that the provision of a continuousshaping work in the final shaping or deformation step results in anentirely uniform structural arrangement of the wheel dish, and thatvirtually no,

spring-back resiliency of the wheel dish occurs even when usingmaterials of maximum strength and of unfavorable shaping properties, sothat the adjusted shape can be maintained most exactly. Furthermore, itis surprising that the workpiece produced in accordance with the methodof the invention has an extremely smooth surface, while substantialscoring occured in the known method.

Additionally, due to the fact that a limited portion of the shaping workonly has to be exerted in the second run or operation, a wall thicknessreduced as desired can be obtained even in the case of workpieces whichare difficult to shape, so that this provides in the field of wheelconstruction for automotive vehicles, the possibility of producing wheeldishes having reduced wall thickness and, therefore, lower unsprungmasses by employing materials of high strength. Further, the uniformstructure or texture of the finished wheel dish, in a manner surprisingthe expert, results in uniform strength of the wall thickness of thewheel dish regardless of the degree of shaping. The abovementioned,reduced spring-back resiliency of the finished part which is obtained bythe smaller proportion of the draw spinning work in the second run ofoperation, allows to substantially improve the spring-back resiliencyand, thus, the accuracy to size in comparison with conventional wheeldishes, even in the case of materials which are difficult to shape.

With known construction, the draw spinning machine according to theinvention comprises two or more shaping rollers. The feed or advance ofthe rollers is effected, in known manner, by a hydraulic copying deviceeach; however, each feed cylinder of each roller has provided thereon aseparate copying device. A

leading auxiliary template protruding beyond the contour of the maintemplate, controls the spinning rollers in order to produce thetemporary shape in the first pass over the workpiece. For the secondpass or run, the auxiliary template is withdrawn behind the maintemplate so that the latter may be scanned for the subsequent drawspinning operation.

-In order that the two abovementioned operations may be carried outduring one clamping period or cycle of the workpiece, combined spinningrollers are used. The combined spinning rollers according to theinvention comprise a pair of peripheral radii of different size andarranged in tandem, whereby a larger radius for spinning is provided inthe front region of the roller, which is followed by a smaller radiusfor the draw or stretch spinning operation. The first smaller radius ismainly active in the first operation cycle, i.e. production of thepreform, while the second, smaller drawing radius becomes active in thesecond step of operation, i.e. drawing into the final shape. In view ofthe fact that in the first step of operation the ronde is stillpositioned perpendicularly to the machine axis, when the spinningrollers are advanced, the larger spinning radius thereof will firstengage the ronde and effect the shaping in the spinningcycle. It is notbefore the second run over the workpiece when the ronde already shows agreat component directed parallel to he machine axis, that the smallerdrawing radii at the outer sides of the spinning rollers come intoengagement with the workpiece, while the ronde is already turned overinwardly relative to the larger spinning radius.

Since a separate control means is provided for each of said spinningrollers, both pinning rollers may operate in different positions and maybe moved in different peripheral contours. Also, it is possible toemploy differently shaped spinning rollers.

Furthermore, since the auxiliary template is formed as a pivotabletemplate, the preform can be shaped in a plurality of shaping runs ifthe shaping properties of the material employed are of very unfavorablenature. The use of a combined spinning roller having two differentshaping radii, provides the advantage that two principally differentshaping processes can be performed with one and the same rollers duringone clamping cycle of the workpiece.

For the adjustment or control of the continuously applied deformationenergy in the final shaping operation, it is advantageous if the shapingspeeds can be selected continuously and as desired during the run overthe workpiece. To this end, contact elements control the speed ofadvance of the spinning rollers in every position of advance thereof,whereby the degree of the speed of advance for both shaping operationscan be preselected at a control desk. The different speeds join eachother with continuous transition.

Now, in all of the shaping operations, especially in the draw spinningoperation, the shaping speed is selected in such way in relation to theposition of the spinning rollers that uniform deformation energy isexerted for every increment of travel. In addition to the formation of auniform structure of texture, this ensures that the draw spinningmachine is loaded uniforrnly and without any load peaks, and the energyconsumption takes place likewise without any peak values. Apparently,the machine may thereby be designed with more favorable connected load(value), and the draw spinning machine is subject to less wear, whichmeans that this machine may be of correspondingly lighter constructionand of improved economy.

Accordingly, the method according to the invention for the production ofwheel discs or dishes, on the whole, provides a number of advantageswhich could not be foreseen by the expert. Rather, the expert wouldassume that the performing of two roller passes or runs in the method isdisadvantageous in economical respects.

As shown in the FIGURE, the draw spinning machine according to theinvention is provided with a pair of oppositely arranged spinningrollers 6 which are concentrically positioned with respect to thespinning chuck 2 and the pressing spindle 3. The ronde or circular disc1 to be shaped is clamped between the spinning chuck 2 and the pressingspindle 3, whereby the centering of the ronde is effected by means of astud 4 on said pressing spindle 3. The turning tool or spinning chuck 2is rotated, in known manner, by an electric motor through a transmissiongear, while the spinning rollers 6 and the pressing spindleare likewisemoved by hydr'aulic means, in known manner.

In order to shape the ronde 1 into theintermediate form or temporaryshape 5, the spinning rollers 6 which are mounted within roller bearings7, are moved along the contour of the auxiliary template 8 by means of ahydraulic copying system 9. In this operation, the spinning shoulder 10of the spinning rollers 6 is in contact with the ronde 1 or 5,respectively, because the ronde which extends perpendicularly from themachine axis, apparently, engages the front face of the spinning rollersat 10.

Upon completion of the first working operation, the spinning rollers arereturned into their starting position by means of an automaticswitch-over means. The auxiliary template 8 is withdrawn behind thecontour of the main template 12 by means of a feed device 11, and in thesubsequent second operation, the respective spinning roller 6 is causedto follow the contour of the main template 12 by the hydraulic copyingsystem 9. In the course of this second working operation, the machinemainly performs a drawing or stretching work so that the thick wallthickness or the temporary shape 5 is drawn to the reduced wallthickness of the final shape 13 of the wheel dish. During thisoperation, the drawing shoulder 14 having a relativelysmall radius onthe spinning roller 6 is in engagement with the intermediate shape 5 andthe metal is now displaced primarily inwardly to the spinning chuck. Asbest seen in the drawing, the drawing shoulder 14 has a curvature formedwith a smaller radius than the curvature for the spinning shoulder 10which is formed with a larger radius. Of course, the larger radiusshoulder 10 is located closer to the spinning axis than is the smallerradius shoulder 14.

By means of a central control desk which provides all of the controlpulses necessary for automatic opera tion, the shaping speed can bevaried in continuous manner in the course of the two working operations.The change of speeds is effected by means of a limit switch controlwhich is operated during the respectively successive shaping operations.The different shaping speeds may be preselected on the control desk inknown manner.

Upon completion of the shaping process, an ejector urges the finishedwheel disc or dish 13 from the spinning chuck 2 against the pressureexerted by the headstock spindle 3. The ejector stops in the ejectionposition. Thereafter, the headstock spindle 3 moves back still further,and the finished wheel dish 13 drops onto a discharge device. In thisway, damage to the spinning chuck during the ejection of the finishedwheel dish 13 is avoided because the wheel dish drops only in a positionbeyond the plane wherein the outermost outline of the spinning chuck iswithin the extension of the flanges of the wheel dish.

What we claim is:

l. A method of producing dish-shaped articles from a circular blankcomprising the steps of: clamping the blank to a spinning chuck, spinshaping the blank into a curved intermediate shape in air withoutabutment against said chuck at a first predetermined speed by movingspinning rollers along a first predetermined path for the spinningoperation, changing the speed of the spinning rollers during a drawspinning operation and imparting uniform deformation energy for theincrements of travel of the spinning rollers during the reduction incross-sectional thickness of the blank, and moving said spinning rollersalong a second discrete path and draw spinning of the blank to the finalshape at speeds less than said predetermined speed.

2. A method in accordance with claim 1 including the step of reversingthe direction of travel of said spinning rollers between traveling alongsaid first and second paths.

3. A method in accordance with claim 1 including the step of ejectingthe finally-shaped article from the spinning chuck while avoiding damagethereto.

4. In a draw spinning apparatus, a rotatable spinning chuck having acontoured surface thereon, means for clamping a circular-shaped blank tosaid chuck with the outer peripheral portion spaced from said counteredchuck surface, at least two draw spinning rollers each having spinningshoulders for engaging the outer peripheral portion of said blank andfor shaping by spinning the outerperipheral portion to the curvedintermediate shape during a first run, first control means including afirst template means for controlling the movement of said spinningrollers along a first path during the spinning of said blank to saidintermediate shape, draw spinning shoulders on each of said spinningrollers for drawing and spinning the intermediate shaped blank againstsaid contoured surface while reducing the cross-sectional thickness ofsaid blank and re-shaping the intermediate shape into a final shape, andsecond control means including a second template means for controllingthe movement of said spinning rollers and said draw and spinningshoulders along a second path distinct from said first path for formingof the blank into a final shape from said intermediate shape.

5. An apparatus in accordance with claim 4 in which each of saidspinning shoulders has a larger radius than the radius of said drawspinning shoulders, said draw spinning shoulders being located radiallyoutwardly of said spinning shoulders from a rotational axis for saidspinning roller.

6. An apparatus in accordance with claim 4 in which said first templatemeans for controlling the path of the spinning operation is locatedadjacent said template means for controlling the path of the spindrawing operation and in which means are provided for displacing one ofsaid template means to allow use of the other one of said templatemeans.

7. An apparatus in accordance with claim 4 in which said spinningrollers are rotated at a higher speed for the spinning operation and ata slower speed for the draw spinning operation, the latter operationbeing conducted with uniform deformation energy.

1. A method of producing dish-shaped articles from a circular blankcomprising the steps of: clamping the blank to a spinning chuck, spinshaping the blank into a curved intermediate shape in air withoutabutment against said chuck at a first predetermined speed by movingspinning rollers along a first predetermined path for the spinningoperation, changing the speed of the spinning rollers during a drawspinning operation and imparting uniform deformation energy for theincrements of travel of the spinning rollers during the reduction incross-sectional thickness of the blank, and moving said spinning rollersalong a second discrete path and draw spinning of the blank to the finalshape at speeds less than said predetermined speed.
 2. A method inaccordance with claim 1 including the step of reversing the direction oftravel of said spinning rollers between traveling along said first andsecond paths.
 3. A method in accordance with claim 1 including the stepof ejecting the finally-shaped article from the spinning chuck whileavoiding damage thereto.
 4. In a draw spinning apparatus, a rotatablespinning chuck having a contoured surface thereon, means for clamping acircular-shaped blank to said chuck with the outer peripheral portionspaced from said countered chuck surface, at least two draw spinningrollers each having spinning shoulders for engaging the outer peripheralportion of said blank and for shaping by spinning the outer peripheralportion to the curved intermediate shape during a first run, firstcontrol means including a first template means for controlling themovement of said spinning rollers along a first path during the spinningof said blank to said intermediate shape, draw spinning shoulders oneach of said spinning rollers for drawing and spinning the intermediateshaped blank against said contoured surface while reducing thecross-sectional thickness of said blank and re-shaping the intermediateshape into a final shape, and second control means including a secondtemplate means for controlling the movement of said spinning rollers andsaid draw and spinning shoulders along a second path distinct from saidfirst path for forming of the blank into a final shape from saidintermediate shape.
 5. An apparatus in accordance with claim 4 in whicheach of said spinning shoulders has a larger radius than the radius ofsaid draw spinning shoulders, said draw spinning shoulders being locatedradially outwardly of said spinning shoulders from a rotational axis forsaid spinning roller.
 6. An apparatus in accordance with claim 4 inwhich said first template means for controlling the path of the spinningoperation is located adjacent said template means for controlling thepath of the spin drawing operation and in which means are provided fordisplacing one of said template means to allow use of the other one ofsaid template means.
 7. An apparatus in accordance with claim 4 in whichsaid spinning rollers are rotated at a higher speed for the spinningoperation and at a slower speed for the draw spinning operation, thelatter operation being conducted with uniform deformation energy.